1. Field of the Invention
This invention relates to a reactive black dye containing acetoxyethyl sulfone moiety and more particularly, to the reactive black dye containing acetoxyethyl sulfone moiety of the following formula 1, which is characterized by lessening the loss of dyes in filtering process owing to the low solubility by introducing the aminophenyl-.beta.-acetoxyethyl sulfone moiety, saving the cost for waste water treatment by using a small amount of salt in salting-out process and furthermore obtaining bright color with high dyeing yield and good substantivity: ##STR2##
wherein M is an alkaline metal atom. PA1 wherein M is an alkaline metal atom. PA1 wherein M is an alkaline metal atom.
2. Description of the Related Art
Conventionally, salting-out method has been adapted in order to isolate dyes from reaction mixture after synthesizing the reactive dyes. However, if aminophenyl-.beta.-sulphatoethylsulfone is used as an intermediate in the course of manufacturing vinylsulfone-based reactive dyes, spray-dry method is adapted or large amount of salts is used because high water-solubility of dyes hinder the salting out. The isolation of dyes by spray-drying or by using large amount of salts may cause environmental pollution with waste water containing a good deal dyes and salts and eventually require much expenses on sewage treatment.
Especially, reactive black aminophenyl-.beta.-sulphatoethylsulfone group has problems such as putting a reddish hue and lowering its substantivity because of high water-solubility.
Recently, in some developed countries such as European countries and U. S. A., there is restriction on salt concentration in dye waterwaste, thus continuous studies have been conducted in order to obtain low-salt dye and succeeded in marketing. In addition, the liquid dyes are used more favorably because they can be exactly measured and from which the automatization of dyeing process and the promotion of worker's health can be achieved. Therefore, the highly concentrated dyes by removal of salts are required for the manufacture of the stable liquid dyes.
Therefore, in comparison with dyes synthesized with aminophenyl-.beta.-sulphatoethylsulfone group, salting-out is generally easier in the dyes synthesized with aminophenyl-.beta.-acetoxyethylsulfone group of following formula 2, which has relatively low water solubility: ##STR3##
In synthesizing process of dyes with using aminophenyl-.beta.-acetoxyethylsulfone group of the above formula 2, it is possible to lower the concentration of salt in water waste because only a small amount of salt is used in salting-out process than the conventional dyes. Also, it is cost-effective in sewage treatment because only a small amount of dyes is lost during the filtering owing to low solubility of dyes. Furthermore, thus prepared dyes has a high purity containing a small amount of salt and be able to lower the concentration of salt and make it easier desalting process in manufacturing liquid dyes.
The composition of the above formula 2 is already known and its manufacturing method is also disclosed in various documents. Among the method, one preparation method of 4-aminophenyl-.beta.-acetoxyethylsulfone is expressed in the following Scheme1(Japanese unexamined publication Sho 81-22354; German Patent No 2 929 107): ##STR4##
According to the above Scheme1, 4acetaminophenyl-.beta.-hydroxyethylsulfone and 98% of sulfuric acid is reacted to get a mixture of 70% of above formula 2 and 30% of above formula 3, and it is reported that the dyes synthesized with the mixture shows good dyeing properties. However, it has a problem that the substantivity is lowered because of high water-solubility due to the existence of 4-aminophenyl-.beta.-sulphatoethylsulfone.
But no report has been made on synthesizing reactive black dyes introducing aminophenyl-.beta.-acetoxyethylsulfone group of the above formula 2.